More news today out of the Food and Drug Administration — so while I’m still writing my follow-up to last week’s news on growth promoters, I want to toss this up first. The latest: The FDA has announced that it is formally reconsidering “antibacterial” soaps and other personal-care products, charging that the antibacterial ingredients confer no benefit over regular soap and water while carrying extra risks.

In a draft rule that will be published Tuesday in the Federal Register, the agency calls for manufacturers of consumer antibacterial products to begin providing data that shows the ingredients are both safe for daily use, and also more effective than plain soap and water. Deep in the 137-page rule, it also raises the issue that’s most interesting to me: whether the routine use of these products causes bacteria to develop resistance against the active ingredients, and against antibiotics as an unintended side effect.

Antibacterial products are a vast market; according to the FDA there are more than 2,000 currently for sale to consumers. (NB: This rule does not cover antibacterial hand-sanitizers; neither does it include the kind of washes and wipes used in healthcare.) The announcement today opens a 6-month comment period that ends next June. It will be interesting to see where this goes.

For background: The FDA first judged antibacterial soaps and washes safe and effective in 1994, but research conducted since then has led to a reconsideration. That re-examination was driven, in part, by European Union disquiet over alleged effects of the main antibacterial ingredient, triclosan (and its solid-product form triclocarban) (More background in this post.) The main research findings since have been that triclosan is an “endocrine disruptor,” that is, that it interferes with production and activity of hormones in the body.

Here’s the relevant language from the FDA draft rule:

Since… 1994… new data have become available indicating that systemic exposure to topical antiseptic active ingredients may be more than previously thought. Systemic exposure refers to the presence of antiseptic active ingredients inside and throughout the body. For example, triclosan is an antiseptic active ingredient commonly found in consumer antiseptic hand and body wash products. It is absorbed through the skin and has been found in both human breast milk and urine. Further, triclosan has been found at relatively consistent levels in urine samples collected from a representative sample of the U.S. population since sampling began in 2003. We believe that the consequences of this systemic exposure need to be assessed. (p.35)

Followed by an explanation of the concern for hormonal effects:

One effect of systemic exposure to consumer antiseptic wash ingredients that has come to our attention since publication of the 1994 TFM is data suggesting that triclosan and triclocarban can cause alterations in thyroid, reproductive, growth, and developmental systems of neonatal and adolescent animals. Hormonally active compounds have been shown to affect not only the exposed organism, but also subsequent generations. These effects may not be related to direct deoxyribonucleic acid (DNA) mutation, but rather to alterations in factors that regulate gene expression.

A hormonally active compound that causes reproductive system disruption in the fetus or infant may have effects that are not apparent until many years after initial exposure. There are also critical times in fetal development when a change in hormonal balance that would not cause any lasting effect in an adult could cause a permanent developmental abnormality in a child. For example, untreated hypothyroidism during pregnancy has been associated with cognitive impairment in the offspring. (p.36)

And also followed by a statement of concern regarding the products’ potential ability to stimulate bacterial resistance, not just against these weaker products, but against actual antibiotics as well:

Since publication of the 1994 TFM, there is new information raising concerns about the impact of widespread antiseptic use on the development of antimicrobial resistance. Bacteria use some of the same resistance mechanisms against both antiseptics and antibiotics. Thus, the use of antiseptic active ingredients with resistance mechanisms in common with antibiotics may have the potential to select for bacterial strains that are also resistant to clinically important antibiotics, adding to the problem of antibiotic resistance. Laboratory studies of some of the antiseptic active ingredients evaluated in this proposed rule demonstrate the development of reduced susceptibility to antiseptic active ingredients and some antibiotics after growth in nonlethal amounts of the antiseptic (i.e., low-to-moderate concentrations of antiseptic). These studies provide ample evidence of bacterial resistance mechanisms that could select for antiseptic or antibiotic resistance in the natural setting.

The impact on bacterial resistance in the natural setting (rather than in the laboratory) has not been extensively evaluated. The existing data are very limited in scope. (pp. 37-38)